主要内容

Limiter

动态范围限制器

  • 库:
  • 音频工具箱 /动态范围控制

  • Limiter block

描述

Limiterblock performs dynamic range limiting independently across each input channel. Dynamic range limiting suppresses the volume of loud sounds that cross a given threshold. The block uses specified attack and release times to achieve a smooth applied gain curve.

端口

输入

展开全部

  • 矩阵输入 - 输入的每一列被视为一个独立的通道。

  • 1-D矢量输入 - 输入被视为单个通道。

除非您指定其他输入端口,否则该端口是未命名的。

数据类型:single|双倍的

Dependencies

要启用此端口,请选择从输入端口指定为了阈值(DB)范围。

数据类型:single|双倍的

Dependencies

要启用此端口,请选择从输入端口指定为了膝盖宽度(DB)范围。

数据类型:single|双倍的

Dependencies

要启用此端口,请选择从输入端口指定为了攻击时间范围。

数据类型:single|双倍的

Dependencies

要启用此端口,请选择从输入端口指定为了Release time (s)范围。

数据类型:single|双倍的

Output

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Limiterblock outputs a signal with the same data type as the input signal. The size of the output depends on the size of the input:

  • Matrix input –– The block outputs a matrix the same size and data type as the input signal.

  • 1-D矢量输入 - 块输出N-b-1矩阵(列向量),其中N是1-D矢量中的元素数量。

This port is unnamed until you select the输出增益(DB)范围。

数据类型:single|双倍的

Dependencies

要启用此端口,请选择输出增益(DB)范围。

数据类型:single|双倍的

Parameters

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If a parameter is listed as tunable, then you can change its value during simulation.

主选项卡

操作阈值is the level above which gain is applied to the input signal.

指定阈值(DB)from an input port, select从输入端口指定为了范围。

可调:Yes

For soft knee characteristics, the transition area is defined by the relation

y = x ( x T + W 2 ) 2 ( 2 × W )

对于范围 ( 2 × | x T | ) W , 在哪里

  • y是DB中的输出水平。

  • x是DB中的输入级别。

  • T是DB中的阈值。

  • W是DB中的膝盖宽度。

指定膝盖宽度(DB)from an input port, select从输入端口指定为了范围。

可调:Yes

当该图时,该图会自动更新Limiterblock change.

可调:Yes

攻击时间is the time the limiter gain takes to rise from 10% to 90% of its final value when the input goes above the threshold. The攻击时间parameter smooths the applied gain curve.

指定攻击时间from an input port, select从输入端口指定为了范围。

可调:Yes

Release time是当输入低于阈值时,限制器增益从最终值的90%下降到其最终值的10%的时间。这Release time (s)parameter smooths the applied gain curve.

指定Release time (s)from an input port, select从输入端口指定为了范围。

可调:Yes

  • 财产- - 化妆增益设置为由Make-up gain (dB)范围。

  • 汽车- 在输出时应用化妆增益Limiter块使稳态0 dB输入具有0 dB的输出。

可调:

Make-up gaincompensates for gain lost during limiting. It is applied at the output of theLimiterblock.

可调:Yes

Dependencies

要启用此参数,请设置化妆增益模式parameter to财产

当您选择该参数,the block inherits its sample rate from the input signal. When you clear this parameter, specify the sample rate in the输入样本率(Hz)范围。

可调:

可调:Yes

Dependencies

To enable this parameter, clear theInherit sample rate from input范围。

Advanced Tab

当您选择该参数,an additional output port,G, is added to the block. TheG端口输出DB中每个输入通道上应用的增益。

可调:

当您选择该参数,an additional input portSCis added to the block. TheSCport enables dynamic range limiting of the input signalx使用单独的Sidechain信号。

这datatype and (frame) length input to theSC端口必须与输入相同x港口。

Sidechain输入的通道数必须等于x或等于一个。

  • 侧链channel count is equal to one–– The computed gain,G,基于此通道应用于所有通道x

  • Sidechain通道计数等于通道计数x–– The computed gain,G, for each sidechain channel is applied to the corresponding channel ofx

可调:

  • 解释执行- 使用MATLAB模拟模型®口译员。此选项缩短了启动时间,并且具有与代码生成。在此模式下,您可以调试块的源代码。

  • 代码生成–– Simulate model using generated C code. The first time you run a simulation, Simulink®generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change. This option requires additional startup time, but the speed of the subsequent simulations is comparable to解释执行

可调:

块特征

Data Types

双倍的|single

直接进料

多维信号

Variable-Size Signals

是的

零交叉检测

算法

Limiterblock processes a signal frame by frame and element by element.

  1. N-point signal,x[n], is converted to decibels:

    x dB [ n ] = 20 × 日志 10 | x [ n ] |

  2. xdB[n]passes through the gain computer. The gain computer uses the static characteristic properties of the dynamic range limiter to brickwall gain that is above the threshold.

    If you specified a soft knee, the gain computer has the following static characteristic:

    x sc ( x dB ) = { x dB x dB < ( T W 2 ) x dB ( x dB T + W 2 ) 2 2 W ( T W 2 ) x dB ( T + W 2 ) T x dB > ( T + W 2 ) ,

    whereT是阈值和W是膝盖宽度。

    If you specified a hard knee, the gain computer has the following static characteristic:

    x sc ( x dB ) = { x dB x dB < T T x dB T

  3. 这computed gain,gc[n],计算为

    g c [ n ] = x sc [ n ] x dB [ n ]

  4. gc[n]使用指定的攻击和发布时间参数进行平滑:

    g s [ n ] = { α A g s [ n 1 ] + ( 1 α A ) g c [ n ] , g c [ n ] g s [ n 1 ] α R g s [ n 1 ] + ( 1 α R ) g c [ n ] , g c [ n ] > g s [ n 1 ]

    这attack time coefficient,αA,计算为

    α A = exp ( 日志 ( 9 ) F s × T A )

    发布时间系数,αR,计算为

    α R = exp ( 日志 ( 9 ) F s × T R )

    TA是攻击时间段,由攻击时间范围。TRis the release time period, specified by theRelease time (s)范围。FS是输入采样率,由Inherit sample rate from input或者输入样本率(Hz)范围。

  5. 如果是Make-up gain (dB)参数设置为汽车, the make-up gain is calculated as the negative of the computed gain for a 0 dB input:

    M = x sc ( x dB = 0 )

    给定0 dB的稳态输入,该配置达到了0 dB的稳态输出。化妆增益取决于阈值(DB)膝盖宽度(DB)parameters. It does not depend on the input signal.

  6. 这make-up gain,M,添加到平滑的增益中,gs[n]:

    g m [ n ] = g s [ n ] + M

  7. 这calculated gain in dB,gm[n], is translated to a linear domain:

    g lin [ n ] = 10 ( g m [ n ] 20 )

  8. 这output of the dynamic range limiter is given as

    y [ n ] = x [ n ] × g lin [ n ]

参考

[1] Giannoulis,Dimitrios,Michael Massberg和Joshua D. Reiss。“数字动态范围压缩机设计 - - 教程和分析。”Journal of Audio Engineering Society。卷。60,第6期,2012年,第399–408页。

Extended Capabilities

C/C ++代码生成
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2016a